Figure S1.

Endogenous Abcb1a expression across the hematopoietic system. (A) Representative Abcb1a^AME reporter expression in select cell types from (left to right) bone marrow, spleen, thymus, and lung. cNK, conventional NK cells; FO, follicular B cells; GC, germinal center B cells; imm. B, immature B cells; iNKT, invariant NK T cells; MZ, marginal zone B cells; recirc. mature B, recirculating mature B cells; T1/2 T1 and T2 transitional B cells, T3, transitional T3 B cells; Treg, regulatory T cells; Tnaive, naive T cells. As in Fig. 1, normalized Abcb1a^AME expression across subsets was quantified by comparing ametrine MFIs in identically gated Abcb1a^AME/+ reporter or wild-type B6 cells but is presented in all Abcb1a^AME/+ reporter subsets and all tissues with only a single gray/shaded peak reflecting the distribution of background ametrine expression in all live wild-type B6 cells, gated only on forward/side scatter and viability, from the same tissue. Vertical dotted lines indicate background ametrine MFIs in all wild-type B6 cells. (B) Representative Abcb1a^AME reporter expression, determined by ex vivo flow cytometry and presented as in A, in select myeloid cells from (left to right) spleen, siLP, and lung. cDC, conventional dendritic cells; cMF, classical macrophages; ncMF, nonclassical macrophage; pDC, plasmacytoid dendritic cell. Data are representative of three pairs of B6 wild-type and Abcb1a^AME/+ reporter mice analyzed over two independent experiments in A and B. (C) Fluorescence microscopy of frozen spleen sections from wild-type (B6; left) or MDR1-reporter (B6.Abcb1a^AME/+; right) mice. Native Abcb1a^AME/+ reporter fluorescence (green) and anti-CD11c staining (red) is shown; colocalization of ametrine and CD11c fluorescence is indicated by orange coloring. Magnification ×10; scale bar = 200 µm; representative of five mice per genotype analyzed over two independent experiments.